Frequency domain identification of volterra model for separating ultraharmonic using the technique of half-frequency of the input signal

Abstract

This paper presents a method for the identification of ultraharmonic component with Volterra kernels from a simulated ultrasound echo signal. Due to the fact that using a Volterra series cannot respond to the ultraharmonic component, the purpose of the paper is to develop the identification method for the ultraharmonic using the excitation technique of half-frequency of the input signal. In addition, the model can still be held at subharmonic component. Finally the identifications of Volterra system were studied in frequency domain. Application of this method is to separate only the ultraharmonic component or ultra-subharmonic components for improving contrast-to-tissue ratio (CTR) of ultrasound imaging.